If everyone they are close to also moved to where this guy and his brother live--and so on--they could have quite the 1 easy trick to found a new megacity.
Here's the plan: you and 5 people closest to you move to the same area. Then each of those 5 people moves 5 of their closest people to the same area. Repeat ~13x and we can all finally be together.
So if a mega-city had a billion people. Maybe that's too much, let's say a 100 million people. Let us say this may be possible this century with some innovations in our habitat. So with a 100 million people in this mega-city, how many people can actually live close to each other? Even if you go 3-dimensions (connected skyscrapers), not sure this model will bring people close. Will it?
